KR102097539B1 - Display device with metal mesh and method for manufacturing the same - Google Patents

Abstract

The display element including the metal mesh of the present invention, due to the high adhesion between the patterned photosensitive resin and the copper film, the undercut factor during etching of the copper film is removed, and fine (<10 μm) and precision Metal mesh pattern can be formed.

Description

Display device with metal mesh and method for manufacturing the same

The present invention relates to a display device formed with a metal mesh and a method for manufacturing the same, and more specifically, an under-cut factor is removed during etching of the copper film due to high adhesion between the patterned photosensitive resin and the copper film. The present invention relates to a display device having a metal mesh capable of forming fine (<10 μm) and fine metal mesh patterns and a manufacturing method thereof.

2. Description of the Related Art Recently, as the use of electronic devices equipped with a small display device such as a navigation device or a smart phone is expanded, display devices equipped with input means such as a touch screen panel are widely used.

A touch screen panel (TSP) is an electronic device equipped with an input means for controlling a computer using a hand or a touch pen. The touch screen panel includes a resistive film method that senses pressure, a capacitive method that senses the movement of charges, and techniques for various structures and manufacturing methods have been developed to reduce manufacturing cost and minimize input errors.

The touch screen panel is generally composed of a window substrate, a black matrix layer, a transparent conductive layer, a metal electrode layer, and a primer layer. First, a black matrix layer, a transparent conductive layer, and a metal electrode layer are sequentially formed on a window substrate, and a primer is used. By proceeding in the order of bonding the touch screen panel to the display substrate. Among them, the use of an indium tin oxide (ITO) thin film as a transparent electrode material has become the main type.

The indium tin oxide material has excellent transmittance and electrical properties, but since it uses a rare earth metal, it has a disadvantage that it cannot be used as a flexible material because it is not smoothly supplied, expensive, and has no flexibility.

Therefore, in order to replace the indium tin oxide that is frequently used, many researches have been conducted on transparent electrode materials such as silver nanowires, carbon nanotubes, graphene, and zinc oxide, and some transparent electrode layers using other methods such as metal mesh are also used. Is being used. The metal mesh, which is expected to replace the indium tin oxide film in the transparent electrode material, uses metals such as silver (Ag) or copper (Cu), so it has an advantage of low resistance, but also has a disadvantage of low permeability.

The metal mesh is coated on a transparent material such as a PET film in an orthogonal form and coated very finely to several micrometers invisibly to make the electrode film. It can replace the existing transparent electrode material, indium tin oxide, securing price competitiveness. can do. In addition, it can be applied to a touch screen panel for a flexible display (flexible display) that could not be applied due to the crack characteristics of the existing indium tin oxide.

As the process of miniaturizing the circuit width to 5 µm or less has been developed for the metal mesh technology mainly applied to mid-to-large products so far, the possibility of application to mobile products has increased, and explosive growth is expected in the future touch screen panel market. do.

Metal meshes for touch screen panels are generally sputtering on PET films, or forming metal layers, such as copper (Cu) and silver (Ag), by transfer or plating, and then implement patterns suitable for the applied product and develop and etch. And a peeling process. Prior art for a method of manufacturing a metal mesh is Korean Patent Registration No. 10-1447927, Korean Patent Registration No. 10-1671169.

The first problem to be solved by the present invention is a metal mesh capable of forming a fine (<10 μm) and fine pattern by removing under-cut factors during etching due to high adhesion with a photosensitive material. It is to provide a display device.

The second problem to be solved by the present invention is to provide a method for manufacturing the display device.

The present invention is a polymer substrate to solve the first problem; And a copper film positioned on the polymer substrate and having a plurality of crystalline forms of protrusions formed using an electroless copper plating method.

According to the exemplary embodiment of the present invention, the protrusion of the crystal form may have a shape in which the width of the lower portion is wider than the width of the upper portion.

According to another embodiment of the present invention, the crystal-shaped protrusions may be formed in a polygonal horn shape.

According to another embodiment of the present invention, the protrusion of the crystal form may be a copper crystal having a surface roughness Ra of 100 nm or less.

The present invention provides a polymer substrate to solve the second problem; Performing a pretreatment for electroless plating on the polymer substrate; Forming a copper film having a plurality of crystalline projections on the surface of the pretreated polymer substrate; Forming a photosensitive layer on the copper film having protrusions of the plurality of crystal forms; Forming a mask layer by exposing the photosensitive layer with a mask having a predetermined pattern; And selectively removing the copper film having the plurality of crystalline forms of protrusions by using the mask layer. The present invention provides a method of manufacturing a display device including a metal mesh.

According to another embodiment of the present invention, the protrusion of the crystalline form may have a shape in which the width of the lower portion is wider than the width of the upper portion.

According to another embodiment of the present invention, the crystal-shaped protrusions may be formed in a polygonal horn shape.

The present invention is formed of a microstructure having a uniform roughness on the surface of the polymer substrate, including a copper film having a plurality of crystalline forms of projections on the surface of the polymer substrate, and due to the high adhesion between the patterned photosensitive resin and the copper film, the copper film It is possible to provide a display device having a metal mesh capable of forming a fine (<10 μm) and fine pattern by removing an under-cut factor during etching, and a method for manufacturing the same.

1 is a view for explaining a method of manufacturing a display device formed with a metal mesh of the present invention.
2 is an optical microscope photograph of a metal mesh of Examples and Comparative Examples.
3 is a photograph of the surface of a copper film having a plurality of crystalline projections formed on a surface of a display device formed according to an embodiment of the present invention.
Figure 4 is a contrast picture of the roughness of the copper film formed by the general chemical copper plating method and the copper film formed according to an embodiment of the present invention.

The technique described below may be applied to various changes and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail. However, the present invention is not intended to be limited to specific embodiments, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the technology described below.

As used herein, the term "protrusion of a plurality of crystal forms" may include, but is not limited to, an inverted polygonal horn shape, wherein the polygonal horn refers to a triangular pyramid, a square pyramid, a pentagonal pyramid, a hexagonal cone, and the like. In the drawing, the projections of the crystalline form show a shape in which the width of the lower portion is wider than the width of the upper portion, but the structure and arrangement are not limited thereto, and if necessary, at least any two of the polygonal horn shapes have a mixed shape. May be As used herein, the term “roughness” refers to a value measured by surface roughness Ra unless otherwise specified. The term "copper film" used in this specification may be used in the same sense as a copper crystal layer or a copper layer. The term "display element" used in the present specification may mean a printed circuit board or a flexible printed circuit board.

The present invention provides a display device formed on a polymer substrate, a metal mesh including a copper film having a plurality of crystalline projections formed on the polymer substrate and formed using an electroless copper plating method.

The display device formed with the metal mesh of the present invention is used for a touch screen sensor, and can replace an existing transparent electrode using an indium tin oxide thin film, and is manufactured by a plating method, thereby reducing manufacturing cost. In addition, a uniform roughness and a microstructure are formed on the surface of the molecular substrate, including a copper film having a plurality of crystal-shaped protrusions, and under-cut factors during etching due to high adhesion with a photosensitive material. This is eliminated, and fine (<10 μm) and precise circuit formation is possible.

The protrusions of the plurality of crystal forms may have a shape in which the width of the lower portion is wider than the width of the upper portion, thereby providing improved adhesion to the polymer substrate. Further, the protrusion may be formed in a polygonal horn shape, for example, triangular pyramid, square pyramid, pentagonal pyramid, hexagonal pyramid, conical, etc., may be variously mixed, and the arrangement may be variously modified. The copper film of the present invention is one in which a plurality of crystalline copper seeds are continuously formed in the form of protrusions. Since the surface of the copper film is formed in the form of a projection, the surface area is wide and the adhesion with the photosensitive material is very excellent. Accordingly, an under-cut factor is removed during etching, and fine (<10 μm) and precise circuit formation is possible. The protrusions of the plurality of crystal forms may be copper crystals having a surface roughness Ra of 100 nm or less. Preferably, the roughness Ra is managed to be 1.00 μm or less, 0.66 μm or less, or 0.30 μm or less. The lower limit is not particularly specified, but it is preferable to consider the provision of the minimum adhesive force to be managed at 0.01 µm or more, 0.05 µm or more, or 0.10 µm or more.

The polymer substrate is selected from the group consisting of PC (polycarbonate), PET (polyethylene telephthalate), PEN (polyethylene naphthalate), PES (polyether sulfone), PMMA (poly methyl methacrlate), PAR (polyarylate) and PI (polyimide). It can be one.

1 is a view for explaining a method of manufacturing a display device formed with a metal mesh of the present invention. A manufacturing method of the display device of the present invention will be described with reference to FIG. 1. First, the polymer substrate 101 is prepared in the first step (a). The polymer substrate 101 is a group consisting of PC (polycarbonate), PET (polyethylene telephthalate), PEN (polyethylene naphthalate), PES (polyether sulfone), PMMA (poly methyl methacrlate), PAR (polyarylate) and PI (polyimide) It may be one or more selected from.

In the second step (B), a pretreatment for electroless plating is performed on the polymer substrate 101 to form a pretreatment layer 102. Pre-dipping, catalytic treatment, and reduction treatment may be performed as the pretreatment. The present invention can form a copper film on a polymer substrate without using an adhesive and without physical pressure such as thermal compression, and also has excellent adhesion between each other. For this, pre-treatment must be performed. If the pretreatment step is omitted, the adhesion between the polymer substrate and the copper film is reduced. The pre-dip, catalytic treatment and reduction treatment may be a continuous process. For example, the pre-dip can then be performed to prevent contamination of the catalyst solution and more effectively to adsorb Pd. In addition, the catalytic treatment adsorbs uniform Pd particles on the surface for the chemical copper plating process, and it is preferable to use a catalyst solution having excellent Pd adsorption efficiency. In addition, the reduction treatment may be an activation operation for depositing Pd ions adsorbed during the catalyst treatment to Pd to perform copper plating using an ionization tendency difference during the chemical copper process.

In the third step (c), a copper film 103 having a plurality of crystalline projections is formed on the surface of the pretreated polymer substrate. The copper film may be performed by immersing the polymer substrate in the plating solution composition or spraying the plating solution composition, but the plating step may apply a typical plating time and temperature. The plating solution composition may include a minimum copper component capable of forming a copper seed on the surface of the polymer substrate, and a nitrogen-based component capable of diffusing the copper component as a seed so as to provide a plurality of protrusions on the surface. The copper component may be a component having a mutual reaction force with the nitrogen-based component so as to form a copper seed on the surface of the polymer substrate and to simultaneously grow the seed by the nitrogen-based component. The copper component may be selected from copper sulfate, copper chloride, copper nitrate, copper hydroxide or copper sulfamate, and the nitrogen-based component may be a 5- or 6-ring nitrogen-based component. The 5 or 6 ring nitrogen-based component is a purine-based compound, pyridazine, methylpiperidine, 1,2-di- (2-pyridyl) ethylene, 1,2-di- (pyridyl) ethylene, 2, 2'-dipyridylamine, 2,2'-bipyridyl, 2,2'-bipyrimidine, 6,6'-dimethyl-2,2'-dipyridyl, di-2-pyrylketone, N, N, N ', N'-tetraethylenediamine, naphthalene, 1,8-naphthyridine, 1,6-naphthyridine, tetrathiafurvalene, terpyridine, phthalic acid, isophthalic acid and 2,2'-dibenzoic acid It may be one or more selected from. The copper component is electroless plated to provide a copper ion concentration in an amount of at least 0.5 g / L, preferably 1 g / L to 30 g / L, more preferably 1 g / L to 20 g / L. It may be included in the plating composition is introduced to provide. In addition, when considering the efficiency of a reaction for forming a copper seed on a polymer surface and then growing it, it may be desirable to divide it into small amounts as necessary, and to input it appropriately or continuously during the reaction time. The 5 or 6 ring nitrogen-based component may be included in the plating solution composition in an amount of 0.01 ppm to 1000 ppm, preferably 0.05 ppm to 10 ppm. The protrusions of the plurality of crystalline forms formed as described above may have a shape in which the width of the lower portion is wider than the width of the upper portion, thereby providing improved adhesion to the polymer substrate. In addition, the protrusion may be formed in the form of a polygonal horn, for example, triangular pyramid, square pyramid, pentagonal pyramid, hexagonal pyramid, cone, etc., may be of various mixed forms, the arrangement may be variously modified. Further, the protrusions of the plurality of crystal forms may be copper crystals having a surface roughness Ra of 100 nm or less. The copper film having a plurality of projections in the form of crystals has a uniform and fine roughness, and thereafter, adhesion to a photosensitive material is increased.

On the other hand, the plating is preferably performed in an alkaline environment so that no metal cladding on the substrate is corroded. The plating solution composition may further include a chelating agent, a pH adjusting agent, or a reducing agent. The chelating agent includes, but is not limited to, organic acids such as carboxylic acids and salts thereof. Such carboxylic acids include, but are not limited to, tartaric acid, citric acid, acetic acid, malic acid, malonic acid, ascorbic acid, oxalic acid, lactic acid, succinic acid and salts thereof. The salts include alkali metal salts of organic acids, such as Rochelle salts comprising potassium sodium tartrate and dipotassium tartrate. Chelating agents are also hydantoin and hydantoin derivatives such as 1-methylhydantoin, 1,3-dimethylhydantoin and 5,5-dimethylhydantoin, nitriloacetic acid and alkali metal salts thereof, triethanolamine, ethylenediamine Tetraacetic acid (EDTA) and alkali metal salts thereof, such as tetrasodium ethylenediaminetetraacetate, modified ethylene diamine tetraacetic acid, such as N-hydroxyethylenediamine triacetate, hydroxyalkyl substituted dialkaline triamine, For example, it may include one or more selected from the group consisting of pentahydroxy propyldiethylenetriamine and N, N-dicarboxymethyl L-glutamic acid tetrasodium salt. Preferably, the chelating agent is a Rochelle salt, dipotassium tartrate, or mixtures thereof. The chelating agent is at least 0.5 g / L, preferably 1 g / L to 150 g / L, more preferably 10 g / L to 100 g / L, most preferably 15 g / L to 50 g / L It can be included in the composition in an amount of. The pH adjusting agent may be a variety of compounds known to provide an alkali composition within a desired pH range. For example, the alkali compound includes, but is not limited to, one or more alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Typically sodium hydroxide, potassium hydroxide or mixtures thereof are used. The alkali compound may be included in an amount that provides a pH range of 8 or more, preferably 10 to 14, and more preferably 11 to 13.5. The reducing agent includes, for example, conventional reducing substances such as formaldehyde. Other examples of such reducing agents include, but are not limited to, hypophosphite salts, such as alkali metal hypophosphites, such as sodium hypophosphite, sulfinate compounds, such as sodium hydroxymethanesulfinate. . Reducing agents may also include glyoxylic acid, formaldehyde, boron hydride salts and dimethylamine borane. Such conventional reducing agents are included in a conventional amount, preferably they are contained in an amount of 1 g / L or more, more preferably 5 g / L to 20 g / L. It is preferred that the composition does not contain glyoxylic acid and an environmentally unfriendly reducing agent, and more preferably does not contain an environmentally unfriendly reducing agent such as formaldehyde, boron hydride salt and dimethylamine borane (DMAB). .

After the step (c), it is possible to improve the chemical bonding power, including anti-corrosion treatment (corresponding to anti-tarnish treatment using silane).

In a fourth step (d), a step of forming a photosensitive layer 104 is performed on the copper film 103 having the plurality of protrusions in the crystalline form. The photosensitive layer may form a photosensitive layer by coating a photosensitive resin on the copper film. The photosensitive resin may be a photosensitive film (dry film).

In the fifth step (E), the photosensitive layer 104 is exposed with a mask having a predetermined pattern to form a mask layer 105. At this time, the width of the pattern is preferably 20㎛ or less.

In the sixth step (bar), the mask layer 105 is used to selectively remove the copper film having the plurality of crystalline protrusions. The above step (bar) can be performed by etching. For the etching, an etching solution of a type containing copper chloride as a main component and a type containing nitric acid or sulfuric acid and hydrogen peroxide as a main component may be applied. In the display device of the present invention, undercut factors are removed during etching and fine and precise circuit formation is possible due to the high adhesion to the photosensitive material due to the large surface area of the copper film having a plurality of crystal-shaped protrusions.

Hereinafter, a method of manufacturing a flexible copper-clad laminate of the present invention and a flexible printed circuit board using the same will be described in more detail using examples.

Example: Manufacturing a metal mesh display device

A PET substrate was prepared. The substrate was treated with 90 ml / L sulfuric acid (61.5%) for 20-40 sec to perform a pre-dip. Thereafter, YMT's ion palladium catalyst Cata 855 Cata 855 30 ml / L and sulfuric acid (61.5%) 90 ml / L were treated at 30 to 35 ° C. for 2 to 5 minutes to adsorb palladium on the substrate surface. Then, sodium hypophosphite was used as a reducing agent. The pretreated polymer substrate was immersed in a plating solution at 30-40 ° C. for 5-20 minutes to form a copper seed to prepare a flexible copper-clad laminate. The plating solution was prepared by adding distilled water copper sulfate, sodium hydroxide, pyridazine. A dry film was laminated on the flexible copper-clad laminate, and a mask layer was formed by exposing it with a mask having a mesh pattern having a pattern width of 15 μm. Thereafter, a copper film having a plurality of crystal-shaped protrusions was etched and removed using the mask layer, thereby manufacturing a flexible printed circuit board having a metal mesh shape.

Comparative Example: Manufacturing of a display device formed of a metal mesh by general copper plating

A display device in which a metal mesh is formed by general copper plating was manufactured. The plating solution was prepared by using the same method as in the above embodiment, except that a copper plating layer was formed on the surface of the polymer substrate using a common copper plating solution (product name: SME plating solution).

Evaluation Example 1: Confirmation of precision of line width of metal mesh

The precision of the line width of the metal mesh produced in the above Examples and Comparative Examples was confirmed. 2 is an optical microscope photograph of a metal mesh of Examples and Comparative Examples. As can be seen through FIG. 2, while the metal mesh of the embodiment has a constant line width, it is possible to implement a precise circuit, whereas the metal mesh of the comparative example does not have a constant line width, so it can be seen that it is difficult to implement a precise circuit.

Evaluation Example 2: Confirmation of the roughness of the copper film surface

The protrusions and roughness of the copper film formed in the above example were confirmed.

3 is a photograph of the surface of a copper film having a plurality of crystalline projections formed on a surface of a display device formed according to an embodiment. As can be seen through FIG. 3, it can be confirmed that the substrate of the embodiment is formed with a copper film having a plurality of protruding protrusions in a crystalline form. In addition, Figure 4 is a contrast picture of the roughness of the copper film formed on the substrate by the comparative example and the copper film formed on the substrate according to the embodiment. As can be seen in FIG. 4, since the present invention forms a copper film having a plurality of crystalline forms of protrusions, it can be confirmed that the roughness differs significantly from the copper film formed by general copper plating when implementing the same thickness.

101: polymer substrate 102: pre-treatment layer
103: copper film 104: photosensitive layer
105: mask layer

Claims (7)

Polymer substrates; And
Containing; on the polymer substrate, a copper layer having a pattern in which a plurality of crystalline forms of protrusions formed by using an electroless copper plating method are arranged in a mesh form;
The display device having a metal mesh is formed such that the projections of the crystalline form have a lower width than the upper width. delete According to claim 1,
A display device with a metal mesh, characterized in that the projection of the crystal form is made of a polygonal horn shape. According to claim 1,
The metal element is formed display device, characterized in that the projection of the crystal form is a copper crystal having a surface roughness Ra of 100 nm or less. Providing a polymer substrate;
Performing a pretreatment for electroless plating on the polymer substrate;
Forming a copper film having a plurality of crystalline projections on the surface of the pretreated polymer substrate;
Forming a photosensitive layer on the copper film having protrusions of the plurality of crystal forms;
Forming a mask layer by exposing the photosensitive layer with a mask having a predetermined pattern; And
Including the step of forming a copper layer having a pattern in which a plurality of crystal form protrusions are arranged in a mesh form by selectively removing the copper film having the plurality of crystal form protrusions using the mask layer.
The method of manufacturing a display device in which a metal mesh is formed in which the projection of the crystalline form has a shape in which the width of the lower portion is wider than the width of the upper portion. delete The method of claim 5,
Method of manufacturing a display device is formed with a metal mesh, characterized in that the projection of the crystal form is made of a polygonal horn shape.

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